Histologic, histochemical and electron microscopic studies were made of bone marrow, tonsil and jejunum from patients with Tangier disease. The foam cells in these 3 types of tissues contained 4 morphologically distinct types of lipid inclusions: 1) crystals of cholesteryl esters; 2) droplets which were composed of mixtures of cholesteryl esters and triglycerides; 3) ceroid, and 4) particles which corresponded in size to plasma chylomicrons and very low density lipoproteins (VLDL).